Ian_M's picture

Jumping creature under rock by canal

Observed: 3rd April 2013 By: Ian_MIan_M’s reputation in InvertebratesIan_M’s reputation in Invertebrates
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Description:

Apologies for poor quality photos. Several of these creatures sprang around energetically when the stone they were hiding under was lifted, some jumping several inches into the air. The stone was on damp soil beside a section of canal with a muddy bank (no concrete wall). This one curled up when it began to dry out then uncurled and became lively again when a few drops of water were dripped onto it. (It was put back where it came from after being photographed.)

Identifications
Species interactions

No interactions present.

Comments

stevegregory's picture

or Orchestia cavimana?

I cannot see enough detail in the images to rule out Orchestia cavimana - which a semi-terrestrial species normally found beside watercourses.

jonmortin's picture

I am not familiar with

I am not familiar with Orchestia Steve so I'm not sure. It seemed the right sort of habitat for A.dorrieni and I think it's within it's range (although I can't access NBN at the moment).

stevegregory's picture

Probably is A. dorienni

It is almost certainly A. dorrieni - but I am not sure! It is in range, it is correct habitat, but it is also a place where O. cavimana may turn up (I've been caught out before).

stevegregory's picture

a bit more.....

In Britain there are two species of Amphipoda; Talitridae that can be found inland, both introduced.

Ochestia cavimana will penetrate far inland along major watercourses, but is semi-terrestrial and rarely far from water. It is pale brown and the male is distinctive in having 'boxing' gloves on its 2nd pair of legs. It is not common (yet), but is about.

Arcitalitrus dorrieni (mistaken called A. sylvaticus in the past) is truly terrestrial and can be found far from water, but usually where the ground is damp. It is much darker than Ochestia, and the male 2nd legs look the same as the females. It has become very frequent in south-west England, and increasing in south Wales and Surrey/Sussex area. It occurs as far north as the Scottish Western Isles. I guess it could turn up anywhere in the west (its too cold in the east!).

Other species (3 I think?) are found in 'tropical' glasshouses, but that's another story.

Steve

stevegregory's picture

Landhopper paper published

My paper, 'On the terrestrial landhopper Arcitalitrus dorrieni (Hunt, 1925) (Amphipoda: Talitridae): Identification and current distribution' has been published which should hopefully answer many of the comments above. View or download pdf at http://bmig.org.uk/view/resource/bmig-bulletin.